clojure.pprint — org.clojure/clojure 1.10.3

A Pretty Printer for Clojure

clojure.pprint implements a flexible system for printing structured data in a pleasing, easy-to-understand format. Basic use of the pretty printer is simple, just call pprint instead of println. More advanced users can use the building blocks provided to create custom output formats.

Out of the box, pprint supports a simple structured format for basic data and a specialized format for Clojure source code. More advanced formats, including formats that don't look like Clojure data at all like XML and JSON, can be rendered by creating custom dispatch functions.

In addition to the pprint function, this module contains cl-format, a text formatting function which is fully compatible with the format function in Common Lisp. Because pretty printing directives are directly integrated with cl-format, it supports very concise custom dispatch. It also provides a more powerful alternative to Clojure's standard format function.

See documentation for pprint and cl-format for more information or complete documentation on the Clojure web site on GitHub.

*print-base* clj

The base to use for printing integers and rationals.

*print-miser-width* clj

The column at which to enter miser style. Depending on the dispatch table, miser style add newlines in more places to try to keep lines short allowing for further levels of nesting.

*print-pprint-dispatch* clj multimethod

The pretty print dispatch function. Use with-pprint-dispatch or set-pprint-dispatch to modify.

*print-pretty* clj

Bind to true if you want write to use pretty printing

*print-radix* clj

Print a radix specifier in front of integers and rationals. If print-base is 2, 8, or 16, then the radix specifier used is #b, #o, or #x, respectively. Otherwise the radix specifier is in the form #XXr where XX is the decimal value of print-base

*print-right-margin* clj

Pretty printing will try to avoid anything going beyond this column. Set it to nil to have pprint let the line be arbitrarily long. This will ignore all non-mandatory newlines.

*print-suppress-namespaces* clj

Don't print namespaces with symbols. This is particularly useful when pretty printing the results of macro expansions

cl-format clj

(cl-format writer format-in & args)

An implementation of a Common Lisp compatible format function. cl-format formats its arguments to an output stream or string based on the format control string given. It supports sophisticated formatting of structured data.

Writer is an instance of java.io.Writer, true to output to out or nil to output to a string, format-in is the format control string and the remaining arguments are the data to be formatted.

The format control string is a string to be output with embedded 'format directives' describing how to format the various arguments passed in.

If writer is nil, cl-format returns the formatted result string. Otherwise, cl-format returns nil.

For example: (let [results [46 38 22]] (cl-format true "There ~[are~;is~:;are~]~:* ~d result~:p: ~{~d~^, ~}~%" (count results) results))

Prints to out: There are 3 results: 46, 38, 22

Detailed documentation on format control strings is available in the "Common Lisp the Language, 2nd edition", Chapter 22 (available online at: http://www.cs.cmu.edu/afs/cs.cmu.edu/project/ai-repository/ai/html/cltl/clm/node200.html#SECTION002633000000000000000) and in the Common Lisp HyperSpec at http://www.lispworks.com/documentation/HyperSpec/Body/22_c.htm

code-dispatch clj multimethod

(code-dispatch object)

The pretty print dispatch function for pretty printing Clojure code.

formatter clj macro

(formatter format-in)

Makes a function which can directly run format-in. The function is fn [stream & args] ... and returns nil unless the stream is nil (meaning output to a string) in which case it returns the resulting string.

format-in can be either a control string or a previously compiled format.

formatter-out clj macro

(formatter-out format-in)

Makes a function which can directly run format-in. The function is fn [& args] ... and returns nil. This version of the formatter macro is designed to be used with out set to an appropriate Writer. In particular, this is meant to be used as part of a pretty printer dispatch method.

format-in can be either a control string or a previously compiled format.

fresh-line clj

(fresh-line)

Make a newline if out is not already at the beginning of the line. If out is not a pretty writer (which keeps track of columns), this function always outputs a newline.

get-pretty-writer clj

(get-pretty-writer writer)

Returns the java.io.Writer passed in wrapped in a pretty writer proxy, unless it's already a pretty writer. Generally, it is unnecessary to call this function, since pprint, write, and cl-format all call it if they need to. However if you want the state to be preserved across calls, you will want to wrap them with this.

For example, when you want to generate column-aware output with multiple calls to cl-format, do it like in this example:

(defn print-table [aseq column-width]
  (binding [*out* (get-pretty-writer *out*)]
    (doseq [row aseq]
      (doseq [col row]
        (cl-format true "~4D~7,vT" col column-width))
      (prn))))

Now when you run:

user> (print-table (map #(vector % (* % %) (* % % %)) (range 1 11)) 8)

It prints a table of squares and cubes for the numbers from 1 to 10:

   1      1       1    
   2      4       8    
   3      9      27    
   4     16      64    
   5     25     125    
   6     36     216    
   7     49     343    
   8     64     512    
   9     81     729    
  10    100    1000

pp clj macro

(pp)

A convenience macro that pretty prints the last thing output. This is exactly equivalent to (pprint *1).

pprint clj

(pprint object)

(pprint object writer)

Pretty print object to the optional output writer. If the writer is not provided, print the object to the currently bound value of out.

pprint-indent clj

(pprint-indent relative-to n)

Create an indent at this point in the pretty printing stream. This defines how following lines are indented. relative-to can be either :block or :current depending whether the indent should be computed relative to the start of the logical block or the current column position. n is an offset.

This function is intended for use when writing custom dispatch functions.

Output is sent to out which must be a pretty printing writer.

pprint-logical-block clj macro

(pprint-logical-block options* body)

Execute the body as a pretty printing logical block with output to out which must be a pretty printing writer. When used from pprint or cl-format, this can be assumed.

This function is intended for use when writing custom dispatch functions.

Before the body, the caller can optionally specify options: :prefix, :per-line-prefix, and :suffix.

pprint-newline clj

(pprint-newline kind)

Print a conditional newline to a pretty printing stream. kind specifies if the newline is :linear, :miser, :fill, or :mandatory.

This function is intended for use when writing custom dispatch functions.

Output is sent to out which must be a pretty printing writer.

pprint-tab clj

(pprint-tab kind colnum colinc)

Tab at this point in the pretty printing stream. kind specifies whether the tab is :line, :section, :line-relative, or :section-relative.

Colnum and colinc specify the target column and the increment to move the target forward if the output is already past the original target.

This function is intended for use when writing custom dispatch functions.

Output is sent to out which must be a pretty printing writer.

THIS FUNCTION IS NOT YET IMPLEMENTED.

print-length-loop clj macro

(print-length-loop bindings & body)

A version of loop that iterates at most print-length times. This is designed for use in pretty-printer dispatch functions.

print-table clj

(print-table rows)

(print-table ks rows)

Prints a collection of maps in a textual table. Prints table headings ks, and then a line of output for each row, corresponding to the keys in ks. If ks are not specified, use the keys of the first item in rows.

set-pprint-dispatch clj

(set-pprint-dispatch function)

Set the pretty print dispatch function to a function matching (fn [obj] ...) where obj is the object to pretty print. That function will be called with out set to a pretty printing writer to which it should do its printing.

For example functions, see simple-dispatch and code-dispatch in clojure.pprint.dispatch.clj.

simple-dispatch clj multimethod

(simple-dispatch object)

The pretty print dispatch function for simple data structure format.

with-pprint-dispatch clj macro

(with-pprint-dispatch function & body)

Execute body with the pretty print dispatch function bound to function.

write clj

(write object & kw-args)

Write an object subject to the current bindings of the printer control variables. Use the kw-args argument to override individual variables for this call (and any recursive calls). Returns the string result if :stream is nil or nil otherwise.

The following keyword arguments can be passed with values: Keyword Meaning Default value :stream Writer for output or nil true (indicates out) :base Base to use for writing rationals Current value of print-base :circle* If true, mark circular structures Current value of print-circle :length Maximum elements to show in sublists Current value of print-length :level Maximum depth Current value of print-level :lines* Maximum lines of output Current value of print-lines :miser-width Width to enter miser mode Current value of print-miser-width :dispatch The pretty print dispatch function Current value of print-pprint-dispatch :pretty If true, do pretty printing Current value of print-pretty :radix If true, prepend a radix specifier Current value of print-radix :readably* If true, print readably Current value of print-readably :right-margin The column for the right margin Current value of print-right-margin :suppress-namespaces If true, no namespaces in symbols Current value of print-suppress-namespaces

• = not yet supported

write-out clj

(write-out object)

Write an object to out subject to the current bindings of the printer control variables. Use the kw-args argument to override individual variables for this call (and any recursive calls).

out must be a PrettyWriter if pretty printing is enabled. This is the responsibility of the caller.

This method is primarily intended for use by pretty print dispatch functions that already know that the pretty printer will have set up their environment appropriately. Normal library clients should use the standard "write" interface.